Drought Update Thursday
Thursday, September 19th, 2013
I have that Wooly Bully, Wooly Bully, Wooly Bully song by Sam the Sham and the Pharaoh’s stuck in my head today! Legend has it that if you sing Wooly Bully to a Caterpillar, it will grant you 3 wishes… Just kidding! Thanks to @Dadiosradios95 for the picture of a wooly caterpillar from Missouri. Legend does say that depending upon how large the middle brown section is within the caterpillar, that will tell you how harsh the winter will be. If it is a large brown section, then it will be a mild winter; if it is a small brown section, then the winter will be more harsh. I can’t tell if the caterpillar is all brown or not. According to the legend and the caterpillar below, it could either be a really bad winter or not bad at all!
Heavy Rain & Drought
Recent heavy rains across parts of the nation have helped with the drought in some locations, especially in the Southwest. We’ll talk more about that in just a second, but take a look at the soggy scenario in Chicago from earlier Thursday.
Here are some of the rainfall tallies that came in from PM Wednesday – AM Thursday.
Here are some of the other impressive rainfall tallies that came in from the Midwest from PM Wednesday – AM Thursday
Thanks to a fairly soggy spring, yearly precipitation from normal across the Midwest is still quite impressive in spots. Interestingly, from Kansas City, MO to St. Louis, MO there is a huge spread in precipitation from nearly 6″ below average to nearly 7.5″ above average for the year.
September Rainfall From Normal
It’s not so much that we’re so far behind normal across the Midwest in a longer term sense, but it’s the shorter term “Flash Drought” that is the problem. Since the beginning of Meteorological Summer, it has been quite dry for a number of locations. The image below suggests how much below average precipitation we are for the month of September.
Minnesota “Flash Drought”
Take Minnesota, for example. From early July to mid September, not how more widespread the drought is now compared to just 2.5 months ago!
National Drought: Week to Week
Because of significant rainfall in the Southwest and along the Front Range of the Rockies, we’ve seen a pretty dramatic decrease in the overall drought there. Unfortunately, much of this heavy rain led to flash flooding!
Weather Summary: The combination of ample Gulf and Pacific tropical moisture (in part from Tropical Storms Manuel (Pacific) and Ingrid (Gulf) which inundated Mexico), stalled frontal systems, and upsloping conditions produced widespread heavy to copious rainfall (widespread 2 to 6 inches, locally 12 to 18 inches especially near Boulder, CO) and severe flash flooding in parts of New Mexico and Colorado. Moderate to heavy rains (1.5 to 4 inches) also drenched portions of Arizona, eastern Nevada, Utah, Wyoming, south-central Montana, western sections of Nebraska, Kansas, Oklahoma, and northern and southern Texas. September monsoonal rains have generated welcome relief from the drought in the Southwest, central Rockies, and High Plains, but unfortunately have been accompanied by flash flooding. Elsewhere, a pair of cold fronts during the week brought relief from last week’s unseasonable heat in the Midwest and Northeast, along with light to moderate rain that generally prevented further deterioration of conditions. Hit and miss (mostly miss) showers occurred in the Southeast, with the most significant rains (more than 2 inches) limited to southern Florida. Warm and mostly dry weather returned to the Northwest after a wet first week of September. Wet weather continued across most of Alaska, while decent windward showers returned to the Hawaiian Islands.
Western Drought Improvement (For Some)
The improvement in drought conditions was isolated and mainly from the Four Corners Region into the Front Range of the Rockies. Note how much less of the EXTREME drought (red) there is in parts of Arizona, New Mexico and Colorado.
The Southwest: The robust southwestern summer monsoon exploded with copious rainfall (6 to 12 inches, locally over 18 inches near Boulder, CO) across portions of New Mexico and Colorado, producing severe flash flooding, loss of lives, and the destruction of property and infrastructure. The combination of ample Gulf and Pacific tropical moisture (in part from Tropical Storms Manuel (Pacific) and Ingrid (Gulf) which inundated Mexico), stalled frontal systems, and upsloping conditions produced the widespread rainfall. Other states in the surrounding region (Arizona, Nevada, Utah, southern Idaho, Wyoming, south-central Montana) and the High Plains also received beneficial moisture from the monsoon, not only this week but in weeks past. In Colorado, widespread flooding was realized from these rains on the Cache la Poudre, South Platte, Big Thompson, and St. Vrain Rivers where communities were stranded as roads collapsed. This was a historic flood (estimates are currently a 100 year flood) for the Front Range, and as such, many improvements are warranted. In some cases, 2-3 category improvements were recommended as 3 inches of rain is approximately 20% of the normal ANNUAL total at many locations. This event was not convective activity, but more tropical in nature, falling for several days in succession. This time of the year is also a huge consideration for improvement as it allows for excellent soil moisture storage going into the fall when evapotranspiration rates are much less as compared to the height of the growing season. In New Mexico, similar 4-10 inch totals (minus the excessive 18 inches) fell, also leading to a widespread 1-category improvement statewide, but due to the prolonged 3-year drought, 2-category improvements were very limited. It will be interesting to see how quickly and how much the major reservoirs in New Mexico react to these rains. Similar 1-category improvements were made in Arizona, Utah, Wyoming, and south-central Montana where 2-4 inches of rain diminished long-term deficits. Numerous flood warnings were issued by the NWS in these states, and with no surprise, most USGS stream flow levels were currently at near or record high flows. Although Arizona saw less rain this week, last week’s downpours were enough to increase flows on the Gila River that raised water levels at the Coolidge Dam by 7 feet, with a few more feet still expected.
Wet September (For Some)
For some, this September has been very wet, leading to widespread flooding and flash flooding events.
Due to extreme rainfall late last week/weekend, rainfall amounts have edge into record territory for some. Here are a few nuggets.
There are several locations in Texas that are extremely dry. Take a look at Houston, which is nearly 13″ below normal precipitation for the year. The U.S. Drought Monitor has most of Texas under some type of drought.
Southern Great Plains: In Oklahoma and Texas, general improvements were made in western sections while eastern portions deteriorated. In the Oklahoma Panhandle, copious monsoonal rains that inundated parts of the Southwest and central Rockies and caused flash flooding also soaked the extreme western Panhandle (and southeastern Colorado) with over 5 inches of rain, enough for a 2-category improvement to D1. With lesser totals (1.5 to 3 inches) just to the east, a 1-category improvement was made to the rest of the Oklahoma Panhandle and in northwestern Oklahoma. Similarly, 2 to 4 inches of rain along the KS-OK border was enough to erase D0 in Kay and Osage counties. However, little or no rain along the Red River Valley continued the dry trend in southern sections of the state as D2 and D3 expanded in extreme southern Oklahoma and across much of eastern Texas (and Louisiana). 30-day rainfall was under 25%, while 60- and 90-day precipitation hovered around 50%, creating 3-6 and 4-8 inch deficits, respectively. In contrast, tropical moisture from Tropical Storm Ingrid in the western Gulf pushed enough moisture northward to dump 2 to 7 inches of rain on southern Texas. Frequent tropical showers have brought Brownsville, TX, 11.29 inches of rain so far this month, with Harlingen at 8.14 inches and McAllen at 5.99 inches. Accordingly, drought was reduced a category where the heaviest rains fell.
NOAA’s HPC 5 day rainfall forecast suggests another several inches of rain possible across the Gulf Coast States through early next week.
Thanks for checking in, have a great weekend ahead!
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